William Sheldon assembled a 66 piece “color set” of large cents and colonials that displayed a wide variety of colors that can appear on copper coins, depending on impurities in the coins and what environments they were exposed to. Scroll to pages 183-184 to see the color set. https://issuu.com/goldbergcoins/docs/sale53holmes
There's a problem with that "scale". The limiting criteria, that pretty much everybody agrees with, that defines RED is that 95% or more of the coin must be original mint red. And in that picture on the Red line, #3 is pretty iffy, and #4 and #5 most definitely do not meet that criteria ! Even though we can only see 1 side of the coin. A similar problem almost certainly exist with the Red Brown line for to qualify for the RB designation 5% or more of the coin must be original mint red. I say almost because we can only see 1 side of the coin in that scale, so we don't know for sure. But I'd say that given what we can see, maybe half of them are very iffy for meeting the required criteria to be be RB.
